The present invention relates to a flexible container, such as a resealable storage bag for food products and the like. More particularly, the present invention relates to a resealable bag that is vented for microwave cooking of sealed food products.
Flexible containers, such as plastic bags, for containment or storage of food products and the like are well known. Prior art storage bags include closure mechanisms having interconnecting elements extending along the open end of the bag to provide a resealable access to the interior of the bag. The elements of the closure mechanism are engageable with each other in response to a sliding compression. These closure mechanisms are commonly known as zipper closures. Prior art storage bags include clamping elements that are slidably received by the zipper closure to facilitate opening and closing of the sealable access.
The closure mechanisms of prior art bags provide for sealed enclosure of various products including food products having a liquid component. Consumers commonly use the storage bags for storage of food product in a refrigerator or freezer for later use. The food product being stored in the refrigerator or freezer will frequently be of a type suitable for heating in a microwave oven. However, prior art storage bags do not provide for microwaving of food products in the sealed condition. The sealed enclosure provided by prior art storage bags is subjected to internal pressure during microwave cooking of many food products. The pressure results from expansion associated with a change of a liquid component of the sealed contents into a vapor state during the microwave heating of the bag contents. Prior art storage bags subjected to positive internal pressure from expansion of the liquid into vapor may burst. Alternatively, the positive pressure may force the elements of the zipper closure to disengage from each other leading to spillage of the food product.
Plastic storage bags of the prior art include bags adapted for storage of compressible articles such as clothing. These storage bags include a zipper closure mechanism to provide a resealable access to the interior of the bag. The storage bags also include a one-way valve for removal of air from the bag after the compressible article has been sealed within the interior of the bag. The one-way valve allows for passage of air from the interior of the bag to an exterior location in response to vacuum applied to the bag interior. The one-way valve functions to prevent passage of air in the reverse direction into the interior of the bag. The one-way valve is positioned on one of the panels of the bag to facilitate attachment of a source of vacuum to the valve for removal of air from the sealed interior.
The one-way valves of the prior art storage bags for compressible articles are not suitable for use in venting of a food storage bag. The one way valve will allow for passage of fluid from the bag interior in response to a positive pressure applied to the bag interior as well as the intended application of vacuum from an exterior location through the valve. Therefore, positive pressure applied to the bag contents, by handling and storage of the bag, for example, will result in contained fluids being directed through the valve to the bag exterior. Food storage bags are intended for storage of all manner of food product including food product having a relatively large percentage of liquids. Therefore, undesirable discharge of the liquid through the one-way valve during handling and storage of the bag could result were a storage bag for compressible articles be used to store food products.
According to the present invention, there is provided a microwavable cooking container. The container includes a pair of flexible panels secured together to form a bag having an open end for access to an interior of the bag. The container further includes a closure mechanism for sealing the open end of the bag having elongated interfitting elements extending adjacent the open end of the bag.
The container also includes a valve assembly including a vent member. The vent member includes an internal passage having first and second ends. The vent member is located at the open end of the bag adjacent an end of the closure mechanism such that the first end of the internal passage is in fluid communication with the bag interior. The internal passage provides an exit path for discharge of a pressurized fluid from the interior of the bag. The container further includes a flow limiter operably engaging the vent member adjacent the second end of the internal passage. The flow limiter prevents discharge of fluid from the internal passage in the absence of a predetermined positive pressure in the bag interior. The flow limiter is adapted to permit discharge when a positive pressure equal to or exceeding the predetermined pressure is created within the bag interior.
According to one embodiment of the invention the container includes a closure clamp slidably received by the closure mechanism for opening and closing the access to the bag interior. The flow limiter includes an end portion of the closure clamp adapted to receive at least a part of the vent member adjacent the second end of the internal passage. The end portion of the closure clamp further includes an opening that is substantially aligned with the second end of the internal passage when the vent member is received by the end portion. The flow limiter further includes a burstable seal that extends across the opening to limit discharge of fluid from the internal passage of the vent member. The burstable seal is adapted to burst when a pressure equal to or exceeding the predetermined pressure is created within the bag interior.
According to one embodiment of the present invention, the burstable seal includes a weakened portion comprising a reduced thickness portion of the burstable seal that defines a burst region.